While other traffic apps are somewhat passive, Waze tracks mobile devices as they travel, and uses that information to help analyze traffic speeds and flow.

In addition, the apps users are constantly providing Waze with information about what's happening around them and that information is available to others in real time.

So for example, a driver might say, hey, there's a piece of debris in the left lane on highway 101 near Palo Alto, or there's a stalled car and we're down to one lane at a particular interchange.

Analyst Chris Silva of the Altimeter Group uses the app and finds it helpful.

CHRIS SILVA: When I use Google Maps today, I can see that the highway or freeway that I'm taking may have traffic, and I may have to decide I want to avoid that road. What's different about Waze is that as I'm driving, it will actually tell me, hey, guess what? There's an accident ahead. Get off at this exit so that you can avoid the traffic. I'll show you the way to get to your destination on some alternate roads.

KAUFMAN: Google paid more than a billion dollars for this small Israeli start up. What does it get for its money beyond what is arguably the best traffic navigation app out there?

For one thing, it keeps Waze out of the hands of rivals like Facebook and Apple. Waze has nearly 50 million users and the number is growing rapidly.

In addition, companies are increasingly offering goods and services to consumers based on where they are. So the more location information Google has, the more targeted the offerings can be and the more Google can charge for its ads.

Google says the Waze product development team will remain in Israel and operate separately, at least for now.